1. Field of the Invention
The invention relates to an edible vegetable fat, substantially free of trans unsaturated fatty acid residues, to margarine fat comprising the fat and to edible fat spreads prepared with the margarine fat.
2. The Related Art
Edible fat spreads are products such as shortening, butter, margarine, halvarine, very low fat spreads, e.g. comprising only 20% fat and the like. Usually such products comprise a continuous fat phase in which the fat of the fat phase comprises liquid oil as well as a network of fat crystals which gives structure to the product. Such products do not need to contain an aqueous phase, but often they do and mostly the aqueous phase is present as a dispersed phase, distributed as small droplets in the continuous fat phase. However, fat spreads may also have a continuous aqueous phase. In such case, the fat phase may constitute a dispersed phase distributed finely in the continuous aqueous phase, or it may constitute a second continuous phase. If the spread comprises a continuous aqueous phase it typically includes hydrocolloids, i.e. gelling and/or thickening agents which contribute to the plasticity of the product.
Recent publications have stated that trans unsaturated fatty acid residues have an effect on blood cholesterol levels resembling that of saturated fatty acids (SAFA). This findings have created a consumer demand for products in which the content of trans fatty acid residues is at least considerably reduced, but preferably zero.
Suppliers of edible fat spreads responded rapidly to this new demand and reformulated existing products and introduced new ones in order to provide products having reduced levels of trans unsaturated fatty acid residues or even substantially trans-free products. Spreads without trans unsaturated fatty acid residues have been available for decades. Such spreads are rather soft products which need a chilled storage and which consistency is not appreciated by many consumers. The notably trans-free so-called health spreads therefore have served a relatively small market segment since the early sixties. Until recently, the majority of the vegetable spreads still contained a substantial amount of trans unsaturated fatty acid residues. Particularly for the firmer products, e.g. those meant for cooking and baking, the trans content could be as high as 40-50% of the fat, and even more.
The recent change-over to low or zero trans spreads has caused various problems such as increased brittleness, a poorer melt down behaviour in the mouth, a less good flavour release and serious structural defects, particularly graininess. As an effect of the changed fat composition some of the constituting fat has appeared to crystallize as coarse grains, which are unacceptable for a spread which ought to possess a smooth appearance and mouthfeel.
Further problems occurred in the manufacturing plants. The low or zero trans margarine fats tend to crystallize more slowly, which not only made the fats less plastic and more brittle, but also reduced the throughput of the spread production lines. This was necessary for allowing the spread more time to get a firm enough consistency. Obvious consequences were capacity losses, extra investments and increased costs for labour and energy.
Subsequently products have been developed with clearly improved sensorically perceivable product properties. But for such improvements generally the use of fat fractionation is required, which is a quite expensive processing technique,
The influence of fat composition on the blood lipids profile, one of the main risk indicators for cardiovascular diseases, is expressed by the Keys Number (KN): EQU KN=C12-C16+trans-0.5PUFA,
wherein "C12-C16" indicates the percentage (related to total fat) of saturated fatty acid residues with 12 to 16 carbon atoms, "trans" is the percentage of fatty acid residues containing one or more trans unsaturated double bonds and "PUFA" indicates the percentage of fatty acid residues containing 2 or more double bonds which should be all in the cis-configuration.
The earlier mentioned health spreads typically have a negative Keys Number, which means that they will typically have a beneficial effect on the blood lipids profile.